U.S. regulators are likely to approve Novo Nordisk's long-acting insulin drug in three years after a surprise rejection earlier this month, analysts forecast in a poll. The delay, however, is expected to be costly, with analysts trimming their earnings forecasts for 2017 by over six percent. The U.S. Food and Drug Administration requested more tests on potential heart risks from Novo Nordisk's Tresiba drug, prompting shares in the Nordic region's most valuable firm to fall 13 percent on February 11. Investors had expected the U.S. watchdog to approve Tresiba after a positive recommendation from an advisory panel in November. A Reuters poll found 13 out of 15 analysts expected an eventual approval of the drug between 2014 and 2018, with the average believing it would happen in 2016. One analyst saw a 50 percent chance of eventual approval while another predicted the Danish drugmaker would not overturn the rejection. Data from Thomson Reuters StarMine showed analysts have cut their expectations for Novo's revenues and earnings for each of the next five years in the wake of the FDA decision. Analysts on average have scaled back 2013 sales estimates by 0.9 percent since February 11, while cutting them for 2017 by 3.4 percent. They have also trimmed forecasts for 2017 earnings per share by 6.2 percent. Nine of the analysts in the Reuters poll predicted that the FDA rejection would also have a negative impact on the sale of Tresiba in Europe, where the drug has already been approved.